Unusual Carbon−Carbon Bond Formations between Allylboronates and Acetals or Ketals Catalyzed by a Peculiar Indium(I) Lewis Acid
作者:Uwe Schneider、Hai T. Dao、Shu̅ Kobayashi
DOI:10.1021/ol100450s
日期:2010.6.4
mechanism is proposed in which a single InI center acts as a dual catalyst to activate both reagents sequentially. Contrary to the classic γ-selectivity of allylsilanes (Hosomi−Sakuraireaction), this InI-catalyzed boronovariant displays distinct α-selectivity. Substrate scope and functional group tolerance proved to be excellent.
在I OTf中,已发现它是有效的路易斯酸催化剂,用于用烯丙基硼酸酯对乙缩醛或缩酮进行前所未有的亲核取代。提出了一种超金属化S N 1机制,其中单个In I中心充当双重催化剂,以依次激活两种试剂。与烯丙基硅烷的经典γ选择性(Hosomi-Sakurai反应)相反,此In I催化的硼烷变体表现出独特的α选择性。底物范围和官能团耐受性被证明是极好的。
Efficient and chemoselective acetalization and thioacetalization of carbonyls and subsequent deprotection using InF3 as a reusable catalyst
An efficient and chemoselective method for preparation of acetals and dithioacetals of aldehydes and their deprotection under catalysis of InF3 is described.
描述了一种有效的和化学选择性的方法,用于制备醛的缩醛和二硫缩醛并在InF 3催化下将它们脱保护。
Trimethysilyl triflate in organic synthesis11Part 11 of this series. Part 10: S. Murata and R. Noyori, Tetrahedron Letters 2107 (1981).
作者:R. Noyori、S. Murata、M. Suzuki
DOI:10.1016/s0040-4020(01)93263-6
日期:——
Trimethylsilyl triflate is a powerful silylating agent for organic compounds and acts as a catalyst which accelerates a variety of nucleophilic reactions in aprotic media. The reactions proceed via one-center, electrophilic coordination of the silyl group to hetero functional groups and exhibit unique selectivities.
Catalytic Use of Elemental Gallium for Carbon–Carbon Bond Formation
作者:Bo Qin、Uwe Schneider
DOI:10.1021/jacs.6b06767
日期:2016.10.12
The first catalytic use of Ga(0) in organic synthesis has been developed by using a Ag(I) cocatalyst, crownether ligation, and ultrasonic activation. Ga(I)-catalyzed C-C bondformations between allyl or allenyl boronic esters and acetals, ketals, or aminals have proceeded in high yields with essentially complete regio- and chemoselectivity. NMR spectroscopic analyses have revealed novel transient Ga(I)
The cyanation of acetals and orthoesters by using a stericallycongestedα-cyanoamine as a cyanatingreagent was investigated. The α-cyanoamine effectively facilitated cyanation in the presence of trichlorosilyl triflate to produce a variety of cyanated adducts in excellent yields. Analysis of the reaction mixture by 1H NMR spectroscopy revealed that trichlorosilyl triflate produced an oxocarbenium
研究了使用空间拥挤的 α-氰胺作为氰化试剂对缩醛和原酸酯进行氰化。α-氰基胺在三氟甲磺酸三氯甲硅烷酯存在下有效促进氰化,以优异的产率生产各种氰化加合物。通过 1 H NMR 光谱分析反应混合物表明,三氟甲磺酸三氯甲硅烷基酯产生作为中间体的氧代碳鎓阳离子物质。